Fatal error is_search() with custom page / query

[jnz31]

• I have confirmed this occurs in the most recent version of WordPress, WooCommerce, and Facebook for WooCommerce.
• I have confirmed this occurs when only WooCommerce and Facebook for WooCommerce are active and when using a default WordPress or WooCommerce theme.

✍️ Describe the bug

Fatal error: Uncaught Error: Call to a member function is_search() on bool in /xxx/wp-includes/query.php:703 Stack trace: #0 /xxx/wp-content/plugins/facebook-for-woocommerce/facebook-commerce-events-tracker.php(378): is_search() #1 /xxx/wp-includes/class-wp-hook.php(292): WC_Facebookcommerce_EventsTracker->inject_search_event(Object(WP_Query)) #2 /xxx/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters(NULL, Array) #3 /xxx/wp-includes/plugin.php(551): WP_Hook->do_action(Array) #4 /xxx/wp-includes/class-wp-query.php(1784): do_action_ref_array('pre_get_posts', Array) #5 /xxx/wp-includes/class-wp-qu in /xxx/wp-includes/query.php on line 703

🚶‍♀️ Steps to reproduce

i have a custom page for sale items, where i take the "normal" $wc_query and add taxonomy (f.ex. sale/women) and 'post__in' => wc_get_product_ids_on_sale(). it is based on woocommerce's archive-product.php.

here is my tax_query

global $wp_query, $language;
$tax_query = WC()->query->get_tax_query();

if (array_key_exists('product_cat', $wp_query->query)) :
    $term = explode('/', $wp_query->query['product_cat']);
    if ((is_array($term) && array_key_exists(0, $term) && $term[0] != 'page')) :
        $tax_query[] = [
            'taxonomy' => 'product_cat',
            'field' => 'slug',
            'terms' => $term[0]
        ];
    endif;
else :
    $term = 'all';
endif;

meta_query (only show in-stock items)

$meta_query = WC()->query->get_meta_query();
$meta_query[] = [
    'key' => '_stock_status',
    'value' => 'instock'
];

...custom query:

$args = [
        'post_status' => 'publish',
        'post_type' => 'product',
        'meta_query' => $meta_query,
        'tax_query' => $tax_query,
        'post__in' => wc_get_product_ids_on_sale(),
        'posts_per_page' => 59,
        'orderby' => 'menu_order title',
        'order' => 'ASC',
        'paged' => $paged
];
$wp_query = new WP_Query($args);

✔️ Expected behavior

this is new behavior (client pointed me to the failing sale page on friday), it worked with no issues before (> 6 month), so not sure, what causes this issue.

i now uncommented the contents of inject_search_event() and it works for me.

i attached my template file, the is a function called jnz_output_category_navigation(). it is not related to this issue.
page-sale.php.zip

[budzanowski]

i now uncommented the contents of inject_search_event() and it works for me.

Do you want to say that it started to work again?

[jnz31]

well, yes. if i remove all functionality from inject_search_event() it works. guess, that is not the purpose of the function..

the function generates the error. it is gone now, since i removed all its contents.. guess it will break something else, but at least my template is now working properly..

[haszari]

Hi there @jnz31 - thanks for reaching out.

It sounds like you have some customizations that might be a factor here - we haven't had any reports from other users of this fatal error.

Can you try to reproduce this issue on a clean site running current versions of WordPress, WooCommerce and Facebook for WooCommerce, and a standard theme such as Storefront or Twenty Twenty? If you can reproduce the fatal error without any custom PHP templates, add the details here so we can figure out what's happening.

On the other hand, if this issue is caused by an interaction with your custom template code and a recent update to Facebook for WooCommerce, you'll need to debug your template & query.

[jnz31]

ciao @haszari

i boiled it down a little further: you inject inject_search_event via add_action('pre_get_posts', [$this, 'inject_search_event']); (line 112) so it runs pre query. and inside inject_search_event you call is_search(). thing is: these conditional functions do not work (always return false) since the query did not even run, yet. so this at least throws a php notice.

pre_get_posts runs before WP_Query has been set up. Some template tags and conditional functions that rely on WP_Query will not work. For example, is_front_page() will not work, although is_home() will work. In such cases, you will need to work directly with the query vars, which are passed to the pre_get_posts hook as an argument ($query in examples on this page).
link

here is the fix:

public function inject_search_event($query) {

			if ( ! $this->is_pixel_enabled() ) {
				return;
			}

			if ( ! is_admin() && $query->is_search() && '' !== get_search_query() && 'product' === get_query_var( 'post_type' ) ) {

				if ( $this->pixel->is_last_event( 'Search' ) ) {
					return;
				}

				// needs to run before wc_template_redirect, normally hooked with priority 10
				add_action( 'template_redirect',            [ $this, 'send_search_event' ], 5 );
				add_action( 'woocommerce_before_shop_loop', [ $this, 'actually_inject_search_event' ] );
			}
		}

aka: passing $query as an argument, and using $query->is_search() instead of is_search()
😘

[jnz31]

here is another solution, also involving the use of the $query argument:

        public function inject_search_event($query)
        {

            if (is_admin() || !$query->is_main_query() || !$this->is_pixel_enabled()) {
                return;
            }

            if (is_search() && '' !== get_search_query() && 'product' === get_query_var('post_type')) {

                if ($this->pixel->is_last_event('Search')) {
                    return;
                }

                // needs to run before wc_template_redirect, normally hooked with priority 10
                add_action('template_redirect', [$this, 'send_search_event'], 5);
                add_action('woocommerce_before_shop_loop', [$this, 'actually_inject_search_event']);
            }
        }

[haszari]

Aha, thanks for digging @jnz31 !

[melek]

@jnz31 also shared this error in a post on the .org support forum with a streamlined description of the fix which may be useful here as well:

inside facebook-commerce-events-tracker.php i changed
public function inject_search_event() { to public function inject_search_event($query) {, and
if ( ! $this->is_pixel_enabled() ) { to if ( ! $this->is_pixel_enabled() || ! $query->is_main_query() ) { to solve the issue.

[jnz31]

yo? can someone implement this easy fix plz?!